Someone who consistently fails at everything attempt by said person. It represents someone who is unable to succeed at life, and is mainly depressed.
A person who has no hope.
More specifically, someone whose parents dont love him in any way, shape, or form.

Man, Jesse is such a jfag, he hasn't passed any of his classes, his parents dont love him, and he wants to kill himself.

A pejorative term for non-Japanese who are emulative of Japanese culture, or more often than not, Japanese culture as interpreted through Japanese anime, or otherwise excessively worshipful of Japan and anything Japanese. While some have embraced terms like japanophile, wapanese or otaku, J-Fag is still used exclusively as a slur.

"I was thinking to study Japanese in college, but the stigma created by J-fags made me decide against it."